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(No Model.)

C. CURTIS 8v N. M. JONES.

PAPER PULP DIGESTER.

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llaman 'raras PATENT OFFICE.

v CHARLES CURTIS, OF NEWTON, MASSACHUSETTS, AND NATHANIEL` M.

' JONES, OF BANGOR, MAINE.

PAPER-PU LP DIGESTER.

SPECIFICATION forming part of Letters Patent No. 485,808, dated November8, 1892.

Application tiled April 2,1892. SeralNo. 427,471. (No model.)

cement.

The invention consists in certain improvements, hereinafter describedand claimed, relating to the construction of the digester at the ends ofmanholes.

,Our improved digester comprises an outer shell or casing of suitablematerial which is provided on its interior surface with an acidresistingcomposition, to which is applied another lining of any desirable cement,preferably in slabs or blocks, and having tongues and recesses. The topof the shell or casing is provided with an upwardly-extended collarhaving a flange thereon, which is adapted to serve as a support orbearing for a down- Wardly-extended cylinder or manhole, having acircular shoulder or ilange ou the top thereof, which is adapted to restupon the flange of the upwardly-extending collar of the shell and act asa support for the cylinder or manhole. This cylinder is considerablysmaller in diameter than the collar and is provided on its outerperiphery with corrugations, eX- cept at its lower portion, which isscrewthreaded to receive another flange for a purpose presently to beexplained. The lower portion of the shell or casing is provided withsimilar fittings, although of much smaller dimensions, through whichsuitable connection is made to a blow-off valve for the discharge `ofthe cooked pulp.

In the drawings forming part of this speciication, Figure l is a centralvertical section of our improved digester. Fig. 2 is a detail inperspective of one of the slabs or blocks constituting the inner liningbefore mentioned.

The shell a is composed of any suitable composition to give therequisite durability and rigidity to the structure. On the upper portionthereof collar b is riveted or otherwise secured, and has flange b',serving as a support for cylinder c. Cylinder c, smaller in diameterthan collar b, has also a radiating fiange c', adapted to rest uponvflange b', and extends downwardly through collar b and into the shell afor a short distance. This cylinder c may be of any suitableacid-resisting material-such aluminum, phosphor-bronze, &c.--and may besecured in any suitable manner to flange b, the flange c having adesired number of perforations, as c2 c3, in which plugs may beinserted, said plugs being provided with stops to serve as grips for awrench or appliance used to insert and remove the plugs, the removal ofthe plugs enabling the cement to be poured in through the openings c2c3. The outer periphery of cylinder c has corrugations c1 upon thegreater portion of its' surface, and upon the lower end thereofscrewthreadsc. Anotherflanged,internallyscrewthreaded, is inserted uponthis lower end and adapted to make a tight joint with the topoverhanging blocks composing the inner lin- 111g.

The lower portion of the shell a is provided with fittings somewhatsimilar to the above. Flange f is detachably secured to the shellagainst which rests flange g of tube g, also of acid-resisting material,and provided with corrugations and with screw-threads to accommodateflange 7L. Suitable connections are made, as at t', with a blow-offvalve to free the digester of. cooked pulp. The inner lining is composedof a series of four-sided slabs or blocks e, two adjacent sides of thesame having a portion of the edges recessed on one surface and the othertwo adjacent edges similarly recessed on the opposite side, .thusforming on the four sides tongues c c and recesses e2 c2. Between thesetongues and recesses when the blocks are in place is a packing of anysuitable acid-resisting material. These blocks e are composed of anyrsuitable acid-resisting material which will not be affected by theaction of the chemicals used. The blocks are built up in the shell a, asshown in Fig. l, closely around cylinder c and tube g, the outer vliningbeing iilled in and built up as the blocks c are pnt in place. The topblock is supported in its place by flange d, after which the cement ofthe outer lining is poured in through perforations c2 c3 to ll theannular space between collar b and cylinder c, and so protect theoutershell from any acid that might leak through the joints made byblocks e and flange d. It will of course be understood that flange h oftube g servesA a similar purpose. A further advantage of thisconstruction is that the cylinder c protects the edges of the lining efrom injury from the falling of chips as the digester is filled. Theplugs may then be placed in the perforations and secured in place.

' We claiml. In adigester, the combination of an outer shell, anoutwardly-extended collar thereon having a flange, an inwardly-extendedcylinder in said collar concentric with and of a smaller diameter thansaid collar, a cement lining between the shell and cylinder, saidcylinder being provided with corrugations to engage the said cementlining, an inner lining composed of molded blocks, and a flange screwedupon the inner end of said cylinder and bearing on the inner surface ofthe 'inner lining, substantially as described.

2. In a digester, an outer shell a, an outwardly-extended collar l),having flanges b', an inwardly-extended eXternally-corrugated cylinderc, having flange c', provided with openings for the insertion of thecement lining between said cylinder and collar, an inner lining composedof molded blocks, aflange secured to the inner end of the cylinder andbearing on the said inner lining, and an outer cement lining interposedbetween the shell and cylinder and engaged with the corrugations of thecylinder.

In testimony whereof We have signed our names to this specificatiominthe presence of two subscribing witnesses, this 28th day of March, A. D.1892.

CHARLES CURTIS. NATHANIEL M. JONES. Witnesses:

JONATHAN WILEY, C. F. BROWN.

